EP3666943B1

EP3666943B1 - Method of controlling spindle of spinning machine and spindle control device

Info

Publication number: EP3666943B1
Application number: EP19204483.2A
Authority: EP
Inventors: Naoki Kojima
Original assignee: Toyota Industries Corp
Current assignee: Toyota Industries Corp
Priority date: 2018-11-13
Filing date: 2019-10-22
Publication date: 2021-01-27
Anticipated expiration: 2039-10-22
Also published as: JP7052683B2; JP2020079458A; EP3666943A1; CN111172632B; CN111172632A

Description

The present disclosure relates to a method of controlling a spindle of a spinning machine and a spindle control device.

BACKGROUND ART

A spinning machine such as a spinning frame and a twisting machine is provided with, for example, about two thousands of spindle stations per machine. A spindle is provided for each spindle station in this spinning machine having a plurality of spindle stations. During the operation of the spinning machine, the spindle rotation speed is controlled in accordance with a predetermined speed change pattern.
During the spinning period of the spinning machine, yarn breakages may occur by any cause. The spinning period refers to a period from the start to the end of winding of yarn on a bobbin by the spindle rotation, i.e., one doff period. If the yarn breakages occur during the spinning period, yarn piecing by an operator is required. Thus, there is a demand for preventing the yarn breakages as much as possible.
Japanese Patent Application Publication No. 2002-105772 discloses a technique that reduces the rotation speed of a spindle at a next spinning operation when the accumulated value of the number of the yarn breakages during the spinning period exceeds a predetermined allowable value in view of the fact that yarn breakages tend to occur at a greater spindle rotation speed,. Additionally, the above-cited Publication also discloses a technique that, with the spinning period being divided into a plurality of intervals, reduces the spindle rotation speed for a specific interval at the next spinning operation if the accumulated value of the number of the yarn breakages for the specific interval exceeds a predetermined allowable value set for the interval.
In the techniques disclosed in the above-cited Publication, however, it is configured to reduce the spindle rotation speed at the next spinning operation if the accumulated value of the number of the yarn breakages exceeds the predetermined allowable value, which results in low responsiveness to yarn breakages in the spindle control
EP0634507A1 discloses a method of controlling a spindle of a spinning machine comprising the steps of detecting a number of yarn breakages during a certain time interval, calculating a difference between the target and the detected number of yarn breakages and changing the speed of the spindle based on the calculated difference.
The present disclosure is directed to providing a method of controlling a spindle of a spinning machine and a spindle control device that increase responsiveness to yarn breakages in the spindle control.

SUMMARY

In accordance with an aspect of the present disclosure, there is provided a method of controlling a spindle of a spinning machine in which the spindle is provided for each of a plurality of spindle stations. The method includes a setting process in which a target rotation speed and a target number of yarn breakages for each of a plurality of intervals are set, wherein a spinning period is divided into the plurality of intervals, a detection process in which a number of yarn breakages for the plurality of spindle stations for each interval is detected during the spinning period, a calculation process in which a difference between the number of yarn breakages and the target number of yarn breakages for each interval is calculated during the spinning period, a classification process in which a changing trend in the difference between the number of yarn breakages and the target number of yarn breakages for multiple intervals up to a current interval is classified depending on characteristics of the changing trend of the difference during the spinning period, a change process in which the target spindle rotation speed applied to the next interval based on a result of calculation made in the calculating process and a result of classification made in the classification process during the spinning period, and a control process in which the spindle rotation speed is controlled in the next interval based on a changed target spindle rotation speed during the spinning process.
In accordance with another aspect of the present disclosure, there is provided a spindle control device of a spinning machine on which a spindle is provided for each of a plurality of spindle station. The spindle control device includes a setting unit setting a target spindle rotation speed and a target number of yarn breakages for each of a plurality of intervals during the spinning period, wherein a spinning period is divided into the plurality of intervals, a yarn breakage detection unit detecting a number of yarn breakages for the plurality of spindle station for each interval during the spinning period, a calculation unit calculating a difference between the number of yarn breakages and the target number of yarn breakages for each interval during the spinning period, a classification unit classifying a changing trend of the difference between the number of yarn breakages and the target number of yarn breakages for multiple intervals up to the current interval depending on depending on characteristics of the changing trend of the difference during the spinning period, a changing unit changing the spindle target rotation speed applied to a next interval based on a result of calculation made by the calculation unit and a result of classification made by the classification unit, and a control unit controlling the spindle rotation speed in the next interval based on the based on a changed spindle target rotation speed during the spinning period.
Other aspects and advantages of the present disclosure will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure together with objects and advantages thereof may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:

FIG. 1 is a schematic diagram of a spindle control device according to an embodiment of the present disclosure;
FIG. 2 is a chart showing an example of a setting of the target spindle rotation speed;
FIG. 3 is a chart showing an example of a setting of the target number of yarn breakages;
FIG. 4 is a flowchart showing a method of controlling a spindle according to the embodiment of the present disclosure;
FIGS. 5A and 5B are charts, each showing an example of a pattern of a change in the difference between the number of yarn breakages and the target number of yarn breakages, which is categorized as a stable trend;
FIGS. 6A and 6B are charts, each showing an example of a pattern of the change in the difference between the number of yarn breakages and the target number of yarn breakages, which is categorized as an improving trend;
FIGS. 7A and 7B are charts, each showing an example of a pattern of the change in the difference between the number of yarn breakages and the target number of yarn breakages, which is categorized as a deteriorating trend;
FIG. 8 is a table showing an example of changing the target spindle rotation speed; and
FIG. 9A is a chart showing an example of changing the target spindle rotation speed applied to the next interval to reduce, and FIG. 9B a chart showing an example of changing the target spindle rotation speed applied to the next interval to increase.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiment

The following will describe an embodiment of the present disclosure in detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram of a spindle control device according to the present embodiment.
A spindle control device 10 according to the present embodiment is used for a spinning machine having a plurality of spindle stations (not shown). The spindle control device 10 is configured to control a rotation speed of a spindle 1 provided for each of the plurality of spindle stations. A bobbin 2 is mounted on the spindle 1, and a yarn is wound on the bobbin 2 with the rotation of the spindle1.
As shown in FIG. 1, the spindle control device 10 includes a spindle motor 12, a motor control unit 13 that controls the spindle motor 12, a memory unit 14 that stores various data used for the spindle control, a setting unit 15 that sets the target spindle rotation speed and the target number of yarn breakages, a yarn breakage detection unit 16 that detects the number of yarn breakages, an calculation unit 17 that calculates a difference between the number of yarn breakages and the target number of yarn breakages, a classification unit 18 that classifies a changing trend in the difference between the number of yarn breakages and the target number of yarn breakages, a changing unit 19 that changes the target spindle rotation speed based on the result of calculation made by the calculation unit 17 and a result of classification made by the classification unit 18, and an interval identification unit 20.
The spindle motor 12 serves as a driving power source for rotating the spindle 1. The motor control unit 13 controls the driving of the spindle motor 12 depending on the spindle speed change patterns stored in the memory unit 14.
As shown in FIG. 2, the memory unit 14 stores data indicating the target spindle rotation speed for each interval, i.e., the spindle speed change pattern. In FIG. 2, the vertical axis and the horizontal axis represent the target spindle rotation speed (rpm) and the intervals, respectively. In the present embodiment, as an example, the spinning period is divided into ten intervals from the first interval to the tenth interval from the start of the spinning period. The target spindle rotation speed is set for each interval. The spinning period is determined by the length of yarn to be wound on the bobbin 2. The target spindle rotation speed is set so that the spindle rotation speed increase in a stepped manner from the first interval to the sixth interval, is maintained at the maximum speed from the sixth interval to the ninth interval, and is set at a speed slower than the maximum speed in the tenth interval. As shown in FIG. 3, the memory unit 14 stores data indicating the target number of yarn breakages for each interval. In FIG. 3, the vertical axis and the horizontal axis represent the target number of yarn breakages and the intervals, respectively. The target number of yarn breakages is set so that the target number of yarn breakages reduces in a stepped manner from the first interval to the fifth interval and is set to two or one from the fifth interval to the tenth interval.
The setting unit 15 is provided for an operator who controls the spinning machine to set the target spindle rotation speed and the target number of yarn breakages for each interval when the spinning period is divided in a plurality of intervals. The setting unit 15 includes, for example, a display unit (not shown) showing a screen for setting, and an input unit such as a keyboard (not shown). The target spindle rotation speed and the target number of yarn breakages set by the setting unit 15 are stored in the memory unit 14.
The yarn breakage detection unit 16 is configured to detect the number of yarn breakages occurring in the plurality of spindle stations for each interval during the spinning period. The yarn breakage detection unit 16 includes a yarn breakage detection sensor 21 that detects the occurrence of yarn breakages and a counter unit 22 that counts the number of yarn breakages based on a result of detection made by the yarn breakage detection sensor 21. The yarn breakage detection sensor 21 is provided for each of the plurality of spindle stations. The yarn breakage detection sensors 21 send a detection signal indicating the occurrence of yarn breakages to the counter unit 22 when yarn breakages occurs in their associated spindle stations.
The counter unit 22 is configured to count the number of yarn breakages for the plurality of spindle stations using the detection signals sent from the plurality of the yarn breakage detection sensors 21. The counter unit 22 identifies which interval is the current interval in the spinning period based on an interval identification signal sent from the interval identification unit 20 to the counter unit 22, and counts the number of yarn breakages for each interval.
The calculation unit 17 is configured to calculate the difference between the number of yarn breakages detected by the yarn breakage detection unit 16 and the target number of yarn breakages stored in the memory unit 14 for each interval during the spinning period. The result of calculation made by the calculation unit 17 is sent to the classification unit 18, and the changing unit 19.
The classification unit 18 classifies a changing trend of the difference between the number of yarn breakages and the target number of yarn breakages for a predetermined number of the intervals (multiple intervals) of the plurality of intervals up to the current interval during the spinning period depending on the variations of the changing trend of in the difference. The actual classification method will be described later. The result of classification made by the classification unit 18 is sent to the change unit 19.
The change unit 19 is configured to change the target spindle rotation speed based on the results of calculation made by the calculation unit 17 and the result of classification made by the classification unit 18 during the spinning period, which is applied to the next interval. The changing unit 19 changes the target spindle rotation speed by rewriting the data of the spindle speed change pattern stored in the memory unit 14.
The interval identification unit 20 is configured to identify which interval is the current interval, i.e., the interval at which spinning takes place currently, from the first interval to the tenth interval during the spinning period. In the spinning machine, a length of yarn to be wound on each bobbin 2 is predetermined. Thus, the interval identification unit 20 measures the length of the yarn wound on the bobbin 2 with the rotation of the spindle 1, and identifies which interval is the current interval in the intervals based on the measurement result. The result of identification made by the interval identification unit 20 is sent to the motor control unit 13, the calculation unit 17, the classification unit 18, the change unit 19, and the counter unit 22, respectively.
The following will describe the method of controlling the spindle according to the present embodiment.
As shown in FIG. 4, the method of controlling the spindle according to the present embodiment includes a setting process S1, a detection process S2, a calculation process S3, a classification process S4, a change process S5, and a control process S6.

(Setting process S1)

The setting process S1 is executed by the operator with the above-described setting unit 15. In the setting process S1, as has been described, with the spinning period divided into ten intervals in total, the target spindle rotation speed and the target number of yarn breakages are set for each interval. Data related to the target spindle rotation speed and the target number of yarn breakages are stored in the memory unit 14.

(Detection process S2)

The detection process S2 is executed by the yarn breakage detection unit 16 during the spinning period. If yarn breakages occur in a spindle station, its associated yarn breakage detection sensors 21 send a detection signal that is indicative of the occurrence of yarn breakages to the counter unit 22. The counter unit 22 identifies which interval is the current interval in the spinning period based on the interval identification signal from the interval identification unit 20 to the counter unit 22. Every time the counter unit 22 receives the detection signal from any yarn breakage detection sensor 21, the counter unit 22 adds one to the count of the number of yarn breakages in each interval in the spinning period. Thus, for example, if a detection signal is sent from five yarn breakage detection sensors 21 during the third interval, "five" is detected as the number of yarn breakages for the third interval. If a detection signal is sent from three yarn breakage detection sensors 21 during the fifth interval, "three" is detected as the number of yarn breakages for the fifth interval.

(Calculation process S3)

The calculation process S3 is executed by the calculation unit 17 during the spinning period. The calculation unit 17 calculates the difference between the number of yarn breakages detected in the above-described detection process S2 and the target number of yarn breakages for each interval. For example, if the number of yarn breakages for the X interval is Cx and the target number of yarn breakages for the X interval is Yx, the calculation unit 17 calculates the difference ΔX between the number of yarn breakages Cx and the target number of yarn breakages Yx in accordance with an equation, i.e., ΔX = Cx - Yx. Thus, when the number of yarn breakages Cx and the target number of yarn breakages Yx are same in the X interval, the difference ΔX becomes zero. The difference ΔX becomes a positive value when the number of yarn breakages Cx is greater than the target number of yarn breakages Yx, and the difference ΔX becomes a negative value when the number of yarn breakages Cx is smaller than the target number of yarn breakages Yx, in the X interval.

(Classification process S4)

The classification process S4 is executed by the classification unit 18 during the spinning period. Assuming that the current interval is the fourth interval, the classification unit 18 classifies a changing trend of the difference between the number of yarn breakages and the target number of yarn breakages depending on the characteristics of the changing trend of the difference for the predetermined number of the intervals up to the current interval, e.g., three intervals, namely, the second, third, and fourth intervals.
According to the present embodiment, the X interval, the X - 1 interval, and the X - 2 interval represent the current interval, the last interval, and the interval before last, respectively. The changing trend of the difference between the number of yarn breakages and the target number of yarn breakages for three intervals up to the current interval, i.e., for the X - 2 interval, the X - 1 interval, and the X interval, is classified into one of an improving trend, a stable trend, and a deteriorating trend. For example, it is classified as the stable trend when the difference between the number of yarn breakages and the target number of yarn breakages changes within a predetermined range, which is set within two from the minimum value 0, as shown in FIGS. 5A and 5B. It is classified as the improving trend when the difference between the number of yarn breakages and the target number of yarn breakages exceeds the predetermined range at least in one interval and changes from the positive value region to the negative value region, towards the current interval, as shown in FIGS. 6A and 6B. It is classified as the deteriorating trend when the difference between the number of yarn breakages and the target number of yarn breakages exceeds the predetermined range at least in one interval and changes from the negative value region towards the positive value region towards the current interval, as shown in FIGS. 7A and 7B. For classifying the difference between the number of yarn breakages and the target number of yarn breakages, the variation of the changing trends and the classification method are not limited to the above described examples, but may be modified various manners.

(Change process S5)

The change process S5 is executed by the change unit 19 during the spinning period. The change unit 19 changes the target spindle rotation speed applied to the next interval based on the result of calculation made by the calculation unit 17 and the result of classification made by the classification unit 18 described above.
FIG. 8 is a table showing the reference data for changing the target spindle rotation speed. Such reference data is stored in the memory unit 14 in advance, and the changing unit 19 may read from the memory unit 14 as required. In FIG. 8, the X interval indicates the current interval, and the difference ΔX between the number of yarn breakages and the target number of yarn breakages in the X interval is divided into various criteria, i.e., 4 ≤ ΔX, 0 < ΔX ≤ 3, ΔX = 0, and -3 ≤ ΔX < 0. The criteria for dividing the difference ΔX may be changed arbitrarily. Additionally, in FIG. 8, the changing trend of the difference up to the current interval is divided into the improving trend, the stable trend and the deteriorating trend. The coefficients, K1, K2, K3, K4, K5, K6, and K7 are set for changing the target spindle rotation speed applied to the next interval. The coefficients, K1, K2, K3, K4, K5, K6, and K7 are used to multiply the preset target rotation speed, when changing the target spindle rotation speed to be applied to the next interval. In the following description, a preset target spindle rotation speed corresponds to the target spindle rotation speed that is preset before changing the target spindle rotation speed in the changing process S5. In addition, a changed target spindle rotation speed corresponds to the target spindle rotation speed, the value of which is changed after changing the target spindle rotation speed in the changing process S5. In the change process S5, the change unit 19 selects one of the coefficients based on the result of calculation made by the calculation unit 17 and the result of classification made by the classification unit 18, and changes the target spindle rotation speed by multiplying the selected coefficient and the preset target spindle speed, which was intended to be applied to the next interval. For example, the changing unit 19 selects the coefficient K3 when the result of calculation made by the calculation unit 17 is 0 < ΔX ≤ 3, and the result of classification made by the classification unit 18 is the stable trend, and changes the target spindle rotation speed applied to the next interval by multiplying the coefficient K3 and the preset target rotation speed.
The values of the coefficients, K1, K2, K3, K4, K5, K6, and K7 become greater in this order, which may be expressed as K1 < K2 < K3 < K4 < K5 < K6 < K7. In addition, the coefficient K4 is 1.0, the coefficients K1, K2, K3 are greater than 0 and less than 1.0, and the coefficients K5, K6, K7 are greater than 1.0. Thus, if the coefficient K4 is used for changing the target spindle rotation speed for the next interval X + 1, the target spindle rotation speed does not change before and after changing the target spindle rotation speed (the preset target spindle rotation speed and the changed target rotation speed). On the other hand, when one of the coefficients K1, K2, K3 is applied to changing the target spindle rotation speed, the changed target spindle rotation speed Vb becomes slower than the preset target rotation speed Va as shown in FIG. 9A. In addition, when one of the coefficients K5, K6, K73 is applied to changing the target spindle rotation speed, the changed target spindle rotation speed Vb becomes faster than the preset target spindle rotation speed Va as shown in FIG. 9B. In changing the target spindle rotation speed in the X + 2 interval, which is the interval right after the X + 1 interval, after the target spindle rotation speed has been changed in the X + 1 interval, the target spindle rotation speed in the X + 2 interval may be set at a value calculated by adding the difference between the target spindle rotation speed before changing the target spindle rotation speed (the preset target spindle rotation speed) and the target spindle rotation speed after changing the target spindle rotation speed (the changed target spindle rotation speed) in the X + 1 interval to the value obtained by multiplying the coefficient applied to the X + 2 interval and the target spindle rotation speed before changing the target spindle rotation speed. This is applicable to not only the X + 1 interval and the X + 2 interval, but also the X interval and the X + 1 interval.

(Control process S6)

The control process S6 is executed by the motor control unit 13 during the spinning period. The motor control unit 13 controls the spindle rotation speed in the next interval based on the target spindle rotation speed that is changed in the change process S5 (the changed spindle rotation speed). Specifically, the motor control unit 13 controls the spindle motor 12 so that the spindle rotation speed becomes the changed target spindle rotation speed at the next interval. The motor control unit 13 corresponds to the control unit of the present disclosure.

Effect of the present embodiment

According to the present embodiment, the target spindle rotation speed applied to the next interval is changed based on the calculation result, which is obtained by calculating the difference between the number of yarn breakages and the target number of yarn breakages for each interval and the classification result, which is obtained by classifying the changing trend of the difference between the number of yarn breakages and the target number of yarn breakages during the spinning period. In addition, the spindle rotation speed for the next interval is controlled based on the changed target spindle rotation speed during the spinning period. As a result, the occurrence of yarn breakages during the spinning period may be reflected to the control of the spindle promptly and adequately. Therefore, responsiveness to yarn breakages in the spindle control may be enhanced.
A method of controlling a spindle (1) of a spinning machine in which the spindle (1) is provided for each of a plurality of spindle stations, includes a setting process (S1) setting a target rotation speed and a target number of yarn breakages for each interval, a detection process (S2) detecting a number of yarn breakages for the plurality of spindle stations, a calculation process (S3) calculating a difference between the number of yarn breakages and the target number of yarn breakages, a classification process (S4) classifying a changing trend in the difference for multiple intervals, a change process (S5) changing the target spindle rotation speed applied to the next interval, and a control process (S6) controlling the spindle rotation speed in the next interval based on a changed target spindle rotation speed during the spinning process.

Claims

A method of controlling a spindle (1) of a spinning machine in which the spindle (1) is provided for each of a plurality of spindle stations, the method comprising the steps of:
setting a target rotation speed and a target number of yarn breakages for each of a plurality of intervals, wherein a spinning period is divided into the plurality of intervals;

detecting a number of yarn breakages for the plurality of spindle stations for each interval during the spinning period;

calculating a difference between the number of yarn breakages and the target number of yarn breakages for each interval during the spinning period the method being characterized by comprising the steps of:
classifying a changing trend in the difference between the number of yarn breakages and the target number of yarn breakages for a predetermined number of intervals of the plurality of intervals up to a current interval depending on characteristics of the changing trend of the difference during the spinning period;

changing the target spindle rotation speed applied to the next interval based on a result of calculation made in the step of calculating and a result of classification made in the step of classifying during the spinning period; and

controlling the spindle rotation speed in the next interval based on a changed target spindle rotation speed changed in the step of changing during the spinning process.
A spindle control device of a spinning machine in which a spindle (1) is provided for each of a plurality of spindle stations, the spindle control device comprising:
a setting unit (14) that sets a target spindle rotation speed and a target number of yarn breakages for each of a plurality of intervals during the spinning period, wherein a spinning period is divided into the plurality of intervals;

a yarn breakage detection unit (16) that detects a number of yarn breakages for the plurality of spindle stations for each interval during the spinning period;

a calculation unit (17) that calculates a difference between the number of yarn breakages and the target number of yarn breakages for each interval during the spinning period
the spindle control device being characterized by comprising:
a classification unit (18) that classifies a changing trend of the difference between the number of yarn breakages and the target number of yarn breakages for multiple intervals up to the current interval depending on characteristics of the changing trend of the difference during the spinning period;

a changing unit (19) that changes the spindle target rotation speed applied to a next interval based on a result of calculation made by the calculation unit (17) and a result of classification made by the classification unit (18); and

a control unit that controls the spindle rotation speed in the next interval based on a changed spindle target rotation speed changed by the changing unit (19) during the spinning period.